The most extensively used method currently employed to color hair is by an oxidative process that utilizes one or more oxidative hair coloring agents in combination with one or more oxidizing agents.
Commonly, a peroxy oxidizing agent is used in combination with one or more developers or couplers, generally small molecules capable of diffusing into hair. In this procedure, a peroxide material, such as hydrogen peroxide, activates the developers so that they react with the couplers to form larger sized compounds in the hair shaft to give a variety of shades and colors.
A wide variety of developers and couplers have been employed in such oxidative hair coloring systems and compositions. However, there still exists a need for additional keratin dyeing compounds that can act as both developers and couplers that safely provide color benefits.